#include <iostream>
#include <Eigen/Dense>

using namespace std;
using namespace Eigen;

int main()
{
    Matrix2f A, b;

    A << 2, -1, -1, 3;
    b << 1, 2, 3, 1;

    cout << "Here is the matrix A:\n"
         << A << endl;
    cout << "Here is the right hand side b:\n"
         << b << endl;

    Matrix2f x = A.ldlt().solve(b);
    cout << "The solution is:\n"
         << x << endl;

    return 0;
}
